If mental anomalism is to be interpreted as a thesisunique to psychology, the anomalousness must begrounded in some feature unique to the mental,presumably its rational nature. While the ground forsuch arguments from normativity has been notoriouslyslippery terrain, there are two recently influentialstrategies which make the argument precise. The firstis to deny the possibility of psychophysical bridgelaws because of the different constitutive essences ofmental and physical laws, and the second is to arguethat mental anomalism follows from the uncodifiabilityof rationality. In this (...) paper I argue that bothstrategies fail – the latter because it conflates primafacie and all things considered rationality and theformer because it rests on a false premise, theprinciple of the rational character of belief. Idistinguish four different formulations of thisprinciple and argue that those formulations which areplausible cannot support the argument for mentalanomalism. (shrink)